title: CO2 sensing at room temperature using carbon nanotubes coated core fiber Bragg grating.
abstract: The sensing of carbon dioxide (CO2) at room temperature, which has potential applications in environmental monitoring, healthcare, mining, biotechnology, food industry, etc., is a challenge for the scientific community due to the relative inertness of CO2. Here, we propose a novel gas sensor based on clad-etched Fiber Bragg Grating (FBG) with polyallylamine-amino-carbon nanotube coated on the surface of the core for detecting the concentrations of CO2 gas at room temperature, in ppm levels over a wide range (1000 ppm-4000 ppm). The limit of detection observed in polyallylamine-amino-carbon nanotube coated core-FBG has been found to be about 75 ppm. In this approach, when CO2 gas molecules interact with the polyallylamine-amino-carbon nanotube coated FBG, the effective refractive index of the fiber core changes, resulting in a shift in Bragg wavelength. The experimental data show a linear response of Bragg wavelength shift for increase in concentration of CO2 gas. Besides being reproducible and repeatable, the technique is fast, compact, and highly sensitive.
authors.affiliation: Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore, India.
authors.forename: B N
authors.initials: BN
authors.lastname: Shivananju
authors.forename: S
authors.initials: S
authors.lastname: Yamdagni
authors.forename: R
authors.initials: R
authors.lastname: Fazuldeen
authors.forename: A K
authors.initials: AK
authors.lastname: Sarin Kumar
authors.forename: G M
authors.initials: GM
authors.lastname: Hegde
authors.forename: M M
authors.initials: MM
authors.lastname: Varma
authors.forename: S
authors.initials: S
authors.lastname: Asokan